Instability

A lack of consistent phenotype, usually as a result of uncontrolled genetic changes. These may be due to transposon activity, or in cell lines, to changes in karyotype.

(abbrev. INSTBY)- The tendency for air parcels to accelerate when they are displaced from their original position; especially, the tendency to accelerate upward after being lifted. Instability is a prerequisite for severe weather - the greater the instability, the greater the potential for severe thunderstorms.